1. Field of the Invention
The invention relates generally to communication techniques used between a remote terminal and a host system, and more particularly to ways of reducing the time from initiation of the communication sequence by the terminal to commencement of transaction processing between the terminal and the host.
2. Description of the Related Art
With the advent of microprocessors and advances in telephone system, it has become possible to have many remote terminals call central hosts to access data. One of the common uses for this data access is credit card authorization. When a customer at a remote site wishes to make a credit card purchase, authorization must be obtained to determine if the transaction should be completed and credit extended. The process is initiated by passing the credit card through a magnetic card reader in a terminal or entering the credit card information manually into the terminal. The terminal then proceeds to connect itself through a telephone network to the host system. After the telephone connection is established and the modems establish a communication link, the host system is queried to determine if the transaction should occur and, if so, an acknowledgment is returned to the terminal and the transaction is completed at the remote location.
A problem arises regarding the length of time required for the terminal to access the host in combination with the cost of the telephone or other lines necessary to perform the connection of the modems. If conventional dial-up and modem technology is used, an average time to complete the connection, establish communications and initiate the transaction is on the order of 30 seconds. This has generally been deemed unacceptable in that the consumer at the remote location must wait this time and then a relatively short transaction time before the purchase can be completed. A conventional dial-up line is a relatively inexpensive connection and so of great interest to those parties which must maintain hundreds of these remote locations, but the performance drawbacks have been considered unsatisfactory.
One conventional way to resolve this connection and communication time problem has been the use of a multi-drop leased line. In this environment a number of remote locations are connected to a single leased line. A master modem at a host location sequentially polls the modems in the terminals at the various remote locations to see if they have data to transmit. If they do, communication is established between the two modems and data is transmitted to perform the transaction. While the performance is quite acceptable at approximately 5 to 7 seconds per complete transaction, the cost is in the range of eight times greater than dial-up technology. However, the added cost has been borne by the vendors because the conventional dial-up technology connection time has been unacceptable and no other generally acceptable solutions were available.
A revolution is currently in progress in the telephone communications area with the advent of digital processing and the use of digital computers in switching operations. Large long distance networks operated by inter-exchange carriers (IXC's) and to some extent local exchange carriers (LEC's) are adopting complete digital systems which correspond in varying degrees to the CCITT ISDN standards, the proprietary signalling portion of which is referred to as SS7, or Signaling System 7. These systems, and the various protocols and capabilities of such a system, are known to those skilled in the art. These standards and equipment and the various computer systems which operate them have allowed significant advances in the capability and features which can be supported.
One exemplary feature which has been improved is called a ring down or hot line technique. In a ring down system, the handset of a telephone is lifted, the telephone thus going off-hook, a signalling arrangement detects the off-hook condition and causes a predetermined telephone at a remote location to ring. No dialing is necessary. Conventionally this was done only for short distances using a dedicated line. This technique allowed quick connections but was quite expensive and effectively limited to point-to-point connections in local areas. The possibilities of ring down or hotline circuits have increased greatly with the new SS7 based signalling technology. One exemplary provider of this new service is Sprint, which provides the "VPN Hotline" service. The VPN Hotline service allows more flexibility than the conventional ring down circuit. Preferably, for best performance a direct access line (DAL) is provided from the customer site to a carrier point of presence (POP) at each end, with all switching between the two POP's being handled over the IXC's conventional shared switch network. The insertion of the POP's and the shared switch network allow the connection to be made between any two locations, assuming the locations are connected to the equipment which works according to the new protocol. The system performs basically as follows. The process commences when the caller goes off-hook to initiate a call. This off-hook condition is detected by the signalling equipment in the POP, with the computer system in the shared switch network thus knowing the effective address or identification of the caller. Because of the DAL connection, the caller is considered "on net," that is positively identified by the shared switch network. An address or identification lookup from a computer database is then performed to determine where the call is to be placed. The final destination address or identification is provided by the lookup, with this information being passed through the Signaling System 7 compatible or similar network. The network passes the connection information to the receiving POP and the receiving telephone is made to ring. This VPN Hotline service provides quick access because no actual dialing is done and the LEC switching arrangement is by passed. Instead, the computer system senses via a conventional signalling arrangement that the originator has gone off-hook, performs a table lookup and then initiates the connection process to the answering or receiving telephone. Thus the use of the available advanced technology has allowed the hotline or ring down circuit to be extended across long distances.
One disadvantage of this VPN Hotline System is that it can only be programmed, at present, for a single point to point connection, but this is not a problem in the remote location to a central host for a credit card approval situation. The location of the host is fixed, therefore the lack of outgoing call location flexibility is not a problem. The originating location retains a unique identification, such as a phone number, so the remote location may still receive a call using conventional techniques. The use of the VPN Hotline technique alone allows a savings of approximately 15 seconds over conventional dial-up systems. Where the various portions of time are gained will be explained in detail later. However, if the conventional average time for dial-up line is approximately 30 seconds, as has been determined the various experiments, this reduction of approximately fifteen seconds still leaves approximately 15 seconds total connection establishment time. This is still relatively high and any further reduction is, of course, desirable.
Sprint has developed a more flexible alternative to the VPN Hotline service discussed above. The new service is referred to as "Switched Access VPN." In this service the customer dials the carrier equal access code and an end of dialing code to establish a cut through access to the carrier's network, for example 10333# in the case of Sprint. In the current majority of cases where the Sprint SS7 network is not fully interoperable with the LEC, this dial sequence causes the customer's telephone number to be forwarded to the carrier's POP by an MF signalling sequence which includes as a significant element the automatic number identification (ANI) sequence. The POP performs an identification lookup based on the telephone number to determine which features are available for this user. This lookup determines if the Switched Access VPN feature is available, and if so, which type. If the Switched Access VPN feature is available, the customer is now cleared and now is considered on net. Until the ANI lookup clears the customer, the customer is considered "off net, " that is , unidentified and not secure. Two types of Switched Access VPN are available. In the first, referred to as immediate, only a single destination is available. In that case the POP has retrieved the destination address as part of the lookup and simply provides the destination address through the remainder of the network to establish the connection. In the second type of Switched Access VPN, referred to as delayed, numerous destinations can be accessed. If the POP determines that the second type is set up for this particular calling location, then the POP provides a dial tone to the customer, the customer then provides a destination number, which is the full digit destination on net number, and end of dialing code to the POP. The on net number is the number used internally by the IXC's network. When the POP receives the on net number, preferably a seven digit number, it retrieves a table for that destination number and does a validation lookup to determine if the particular customer is authorized by checking for the ANI information. If not listed, the customer is not authorized and a failure code in the form of a recorded announcement is returned. If listed and thus authorized, the call proceeds. Alternatively, fewer digits can be used in a speed dial arrangement, but the resulting speed dial lookup offsets the dialing of the extra digits. The destination address or identification based on the on net number is used and provided through the network to establish the connection. While some additional time is necessary because of the dialing of the digits, this service provides capabilities to reach multiple destinations.
The previous section described a service referred to herein as MF Switched Access VPN which is used when the POP and the LEC are not fully interoperable using SS7. In certain areas today and more areas in the future, the POP and the LEC are fully interoperable. In these cases the Switched Access VPN sequence is slightly different. After the customer completes the cut through request, the POP and LEC communicate out of band according to the SS7 protocol. Included in this communication is the automatic number identification of the customer. The POP then proceeds as stated above. The interoperable Switched Access VPN service is significantly quicker than the MF Switched Access VPN service because the use of the SS7 out of band signalling greatly reduces the time necessary to transmit the ANI and other signalling information as compared to MF signalling.
As compared to VPN Hotline, delayed MF Switched Access VPN may add as much as 2 seconds in the average case and immediate interoperable Switched Access VPN may be 1 second faster. Delayed, interoperable Switched Access VPN and immediate MF Switch Access VPN will add times between those limits. One advantage of all the Switched Access variations is that connection to the LEC is simplified. Where the original VPN Hotline connections generally required loop start connection to the LEC, the Switched Access variations utilize conventional 1FB or 1MB business line switched connections. The DALs and loop start are no longer required. Thus a small trade off in time greatly simplifies the actual ordering, wiring and provisioning of the system.